Safety venting device



July 14, 1964 F 5, ETAL 3,141,008

SAFETY VENTING DEVICE Filed July 6, 1962 FIEl :ff-fari? eys i l l United States Patent O 3,141,008 SAFETY VENTING DEVICE Francis S. Flick, ak Park, Roy G. Wilkes, Melrose Park, and Walter J. Kudlaty, Elmhurst, Ill., assignors to Flick-Reedy Corporation, a corporation of Illinois Filed July '6, 1962, Ser. No. l207,961 4 Claims. (Cl. 220-5) This invention relates to a safety venting device and more particularly to a safety venting device for tie rod equipped accumulators.

An accumulator is a device for storing fluid under pressure and in such a capacity stores fluid at pressures up to around 3,000 p.s.i. Since an assembled accumulator has no moving parts that are visible to a workman, it is extremely dilficult to look at an accumulator and tell whether or not it has stored fluid under pressure Within it. This situation produces a hazardous and risky operation when it is desired to dismantle an accumulator for maintenance or other reasons. Serious accidents may result from the innocent loosening of the tie rod nuts on a charged accumulator, thereby allowing a jet of high pressure lluid to escape. The fluid pressure is strong enough to violently force the accumulator apart or strip the tie rod threads when they are partially loosened.

The present invention eliminates the above hazards by providing a safety venting device which automatically and safely allows fluid to escape from the accumulator once a tie rod nut is loosened.

It is the primary object of this invention to provideV a new and improved safety venting device for tie rod equipped accumulators.

Another object of this invention is to provide such a safety venting device which will not alter the design or hinder the operation of the accumulator.

Other objects, features and advantages of the invention will be apparent from the following description of a preferred embodiment illustrated in the accompanying drawings, in which:

FIGURE 1 is a side view of an accumulator having the safety venting device of this invention at one end thereof with the parts in position to better illustrate the invention;

FIGURE 2 is an enlarged end View of the accumulator shown in FIGURE 1 with the barrel, passage, O-ring and a portion of the closure plate shown in dotted outline;

FIGURE 3 is a view taken substantially as indicated along line 3 3 of FIGURE 2 showing the relationship between the passage, the tie rod, the cantilevered plate, and the O-ring with the nut loosened on the tie rod for clarity of illustration of the invention;

FIGURE 4 is a plan view taken substantially as indicated along line 4-4 of FIGURE 3 illustrating the relationship between the tie rod nut, the cantilevered plate, and the O-ring.

The accumulator illustrated in the drawings is one involving a free type piston reciprocating in a cylinder of single size. The accumulator generally indicated has a cylinder 11 having a pair of square heads 15 and 18 joined to the cylindrical barrel 11 by a plurality of tie rods 16, generally one in each corner, of the square heads. The construction of the cylinder barrel and heads is held in assembled relation by the tie rods following accepted good practice for the making of high pressure cylinders of machine tool grade. The tie rods, of course, are equipped at each end with nuts 17 and 20 which in assembly apply a predetermined tensile stress to the tie rods and an equal and opposite compression upon the cylindrical barrel 11. As shown in FIGURE 1 tie rod nuts 17 on the outer ends of rods 16 hold the head 15 and the barrel 11 in assembled relation and tie rod nuts 3,141,008 Patented July 14, 1964 ICC 20 on the outer ends of tie rods 19 hold the head 18 and barrel 11 in assembled relation.

Ordinarily, a hydraulic fluid from a pump circuit or other hydraulic circuit is connected with a port 21 so as to be in the upper end of the cylinder 11 beyond an internal -iloating piston 12. The accumulator is loaded by introducing a gas, such as filtered air or nitrogen, through port 22 at the far end of the accumulator so that the gas will be below the internal floating piston 12 within the cylinder 11. In operation, the pump circuit or hydraulic circuit to which the accumulator is attached will during periods when the uid is not needed pump hydraulic fluid into the upper end of the cylinder thus causing the piston 12 to move to the right in FIGURE l compressing the gas in the cylinder. When the system requires a surge of high pressure oil or hydraulic fluid, the accumulator is charged to deliver that oil generally at relatively high rates of flow.

As is illustrated in FIGURE l, the accumulator has no visible moving parts. There is thus no way in which a person can observe an accumulator to determine whether or not it is loaded or unloaded. Maintenance may require that an accumulator be dismantled and under such conditions it is obviously important that the high pressure charge within the accumulator be reduced to more nearly atmospheric pressure. In the present invention, means are provided to insure the venting of the interior of the cylinder of the accumulator upon the rst movements of a maintenance man in starting to disassemble the accumulator.

Referring particularly to FIGURES 2 through 4, a device is employed to vent the interior of the charged side of the accumulator whenever one of the tie rod nuts 17 is first loosened. In order to accomplish the venting, a small drilled passage 25 extends longitudinally or diagonally toward the center and opposite end of the cylinder, through the head 15 adjacent a tie rod 16 but spaced radially inwardly therefrom a sufhcient distance or with enough diagonal angle to be inside the wall of the cylinder 11 at its inner end. The passage 25 thus communicates with the interior of the cylinder and the space which would be charged with gas. It is important to vent the space before any separation of the head and cylinder wall occurs or before thread engagement of the nut on the tie rod is shortened materially. As illustrated in FIGURE 3, the cylinder 11 is provided with an extension 26 extending into a circular groove in the head 15 and this construction is made in accordance with United States Letters Patent No. 2,842,284. It includes a metal-to-metal contact between the outer surface of the extension and the outer surface of the groove in the head. Also, a resilient seal 27 is in the bottom of the groove. Until the head and cylinder wall are separated sufliciently to bring the two metal members out of contact, there may at times be no observable leakage between the cylinder and head.

In order 'to insure that the initial attempt to disassemble the accumulator will vent the interior, the individual passages 25 are placed through at least one head and adjacent each tie rod. The passage is closed by a plate 2S impaled on the adjacent tie rod and extending radially inwardly in superposed relation to the adjacent passage 25. An O-ring 29 or other sealing device is mounted on the underside of the plate in a groove provided for that purpose so as to surround the outer end of the passage 25. As shown in FIGURES 2 and 4, the inner diameter of the -0-ring 29 corresponds to the circumference of the passage 25 so that the bending load on the plate 28 is reduced. When the tie rod nut 17 is tightened to place stress in the tie rod, the cantilevered plate will be brought into face-to-face contact with the head and the O-ring will lill the cavity provided for it providing a pressure sensitive seal around the exterior of the passage 25. So long as there is one passage for each tie rod, loosening of the nut on either end of the tie rod will permit the pressure within the accumulator to lift the plate and thus escape. The loosening of one tie rod will thus vent the interior of the accumulator before there has been sufficient disassembly to allow the separation of the heads from the cylinder barrel of the accumulator.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom for some modifications will be obvious to those skilled in the art.

We claim:

1. A safety venting device for a high pressure pneumatic fluid accumulator and the like, comprising: a cylindrical barrel with a head at each end and a plurality of tie rods equipped with nuts for joining said heads to maintain assembled relation of said barrel and heads and hold fluid at high pressure within the barrel, fluid sealing means between each head and the barrel, a huid escape passage through at least one head adjacent one of said tie rods and communicating with the interior of said barrel, a plate extending under the tie rod nut and over 'the passage, and an O-ring surrounding said passage between the head and plate whereby tightening of the tie rod nut positions the O-ring and plate in sealing relationship with the passage and attempted disassembly of the accumulator by loosening a nut on the tie rod will safely vent pneumatic fluid from the interior of the barrel through said passage.

2. A safety venting device for a high pressure pneumatic luid accumulator and the like, comprising: a cylindrical barrel with a square head at each end and a plurality of tie rods extending through the corners of each head equipped with nuts for joining said heads to maintain assembled relation of said barrel and heads and hold fluid at high pressure within the barrel, sealing means including metal-to-metal contact Vbetween each head and the barrel for sealing the fluid within the barrel, a iluid escape passage lengthwise through each head close to the barrel wall and communicating with the interior of said barrel, a rigid plate extending under the tie rod and cantilevered over the passage, and an O-ring surrounding said passage between the head and plate whereby tightening of the tie rod nut positions the O-ring and plate in sealing relationship with the passage and attempted disassembly of the accumulator by loosening a nut on the tie rod will safely vent pneumatic fluid from the interior of the barrel through said passage.

3. A safety venting device for a high pressure pneumatic uid accumulator and the like, comprising: a cylind rical barrel with a square head at each end and at least one tie rod extending through each corner of each head equipped with nuts for joining said heads to maintain assembled relation of said barrel and heads and hold uid at high pressure within the barrel, sealing means including metal-to-metal contact between each head and the barrel for sealing the fluid within the barrel, a fluid escape passage lengthwise through each head close to the barrel wall and communicatingwith the interior of said barrel, a rigid plate extending under the tie rod cantilevered over the passage, and an O-ring surrounding said passage between the head and plate whereby tightening of the tie rod nut positions the `O-ring and plate in sealing relationship with the passage and loosening a nut on a tie rod allows any high pressure pneumatic fluid in the interior of the barrel to safely vent by lifting the plate and opening the passage without breaking the metalto-metal sealing contact between each head andthe barrel.

4. A safety venting device as specified in claim 4 wherein the heads of the accumulator are provided with a venting passage adjacent each tie rod and a separate rigid plate is movable into and out of sealing position over one of said venting passages under control of tightening and loosening of nuts on said each tie rod whereby loosening of a tie rod on the accumulator will vent the same.

References Cited in the tile of this patent UNITED STATES PATENTS 

1. A SAFETY VENTING DEVICE FOR A HIGH PRESSURE PNEUMATIC FLUID ACCUMULATOR AND THE LIKE, COMPRISING: A CYLINDRICAL BARREL WITH A HEAD AT EACH END AND A PLURALITY OF TIE RODS EQUIPPED WITH NUTS FOR JOINING SAID HEADS TO MAINTAIN ASSEMBLED RELATION OF SAID BARREL AND HEADS AND HOLD FLUID AT HIGH PRESSURE WITHIN THE BARREL, FLUID SEALING MEANS BETWEEN EACH HEAD AND THE BARREL, A FLUID ESCAPE PASSAGE THROUGH AT LEAST ONE HEAD ADJACENT ONE OF SAID TIE RODS AND COMMUNICATING WITH THE INTERIOR OF SAID BARREL, A PLATE EXTENDING UNDER THE TIE ROD NUT AND OVER THE PASSAGE, AND AN O-RING SURROUNDING SAID PASSAGE BETWEEN THE HEAD AND PLATE WHEREBY TIGHTENING OF THE TIE ROD NUT POSITIONS THE O-RING AND PLATE IN SEALING RELATIONSHIP WITH THE PASSAGE AND ATTEMPTED DISASSEMBLY OF THE ACCUMULATOR BY LOOSENINGD A NUT ON THE TIE ROD WILL SAFELY VENT PHENUMATIC FLUID FROM THE INTERIOR OF THE BARREL THROUGH SAID PASSAGE. 